1. Field of the Invention
The present invention relates to rendering devices and, more specifically, to a rendering device which can be incorporated in a drive assistant device. In more detail, the rendering device generates a display image of around a vehicle based on an image captured by an image capture devices fixedly placed in the vehicle.
2. Description of the Background Art
A conventional drive assistant system is exemplarily disclosed in Japanese Patent Laid-Open Publication No. 64-14700 (1989-14700). The drive assistant system is provided with a rudder angle sensor placed in a vehicle for detecting a rudder angle of the steering wheel; a processor for deriving, based on the rudder angle of the steering wheel, a path estimated for the vehicle to take; an image capture device in charge of an area rear, or right and left-side rear of the vehicle; and a display device for displaying a display image. In such drive assistant system, when the vehicle starts moving backward, the display device displays an image captured by the image capture device to show the driver in what state the area behind the vehicle is. When the steering wheel is turned, a path estimated for the vehicle to take is overlaid on the same image. Here, the estimated path is derived based on the rudder angle of the steering wheel. With the help of such image provided by the drive assistant device, the driver can know whether his/her current steering will fit the vehicle into the parking space.
There is another type of conventional drive assistant device exemplarily disclosed in Japanese Patent Laid-Open Publication No. 11-78692 (99-78692). The drive assistant device carries a plurality of image capture devices, and merges plural images captured thereby to generate a display image. For higher speed image merging, every pixel in each of those captured images is mapped to a road surface whereon the vehicle moves. Then, the road surface is viewed from a predetermined virtual viewpoint, and the resulting display image covers the area around the vehicle. In this case, any object observed around the vehicle is projected on the road surface without any height component.
The above conventional type drive assistant devices carry problems as follows.
First, such drive assistant devices are not helpful enough if the parking lot has no marking as white lines defining an individual parking space. The driver thus finds it difficult to exactly figure out where to park in such parking lot.
Second, especially in the conventional drive assistant device of a type merging a plurality of images and generating a display image, no concern is given to the height components of objects appearing in the captured images. As a result, objects in the resulting display image look deformed. It means, assuming that the driver wants to park his/her vehicle between two vehicles positioned behind, as shown in FIG. 7, the resulting display image shows the driver two deformed two vehicles. The driver thus has a hard time to precisely recognize a space between those two vehicle available for his/her vehicle, for example. In such case, an estimated path L is of little help. In other words, with the conventional drive assistant devices, the driver finds it difficult to decide if his/her vehicle fits in the parking space without hitting anything.
Therefore, an object of the present invention is to provide a rendering device, a display image generated thereby being supportive enough for a driver of the vehicle to figure out a parking space available for his/her vehicle. Another object of the present invention is to provide a rendering device, a display image generated thereby being indicative and helpful enough for the driver to decide whether his/her vehicle fits into the parking space without hitting anything.
The present invention has the following features to attain the objects above.
An aspect of the present invention is directed to a rendering device for generating a display image of around a vehicle for drive assistance, and the device comprises a vehicle model storage part for storing a vehicle model representing the vehicle; a path calculating part for calculating an estimated path for the vehicle based on a rudder angle of the vehicle provided by a rudder angle detecting part placed in the vehicle; a receiving part for receiving a captured image of around the vehicle from an image capturing part placed in the vehicle; and an image processing part for generating the display image based on the captured image, the estimated path, and the vehicle model. The display image generated by the image processing part is displayed by a display part placed in the vehicle, and includes the vehicle model arranged on the estimated path.
These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.